Improving Efficiency

Advancements in irrigation methods and practices

With various projects and initiatives for saving water such as groundwater recharge, rainwater harvesting and non-revenue water (NRW) reduction, the water sector has gained a lot of attention in the past few years. The Ministry of Jal Shakti launched the Pradhan Mantri Krishi Sinchayee Yojana (PMKSY) in 2015 with a vision to extend the co­verage of irrigation and improve water use efficiency in a focused manner with end-to-end so­l­utions on source creation, distribution, ma­na­­ge­ment and field application. It is an umbrella scheme having two key components – Acce­le­rated Irrigation Benefits Programme (AIBP) and Har Khet Ko Pani (HKKP).

The irrigation sector is the largest consu­mer of water in India and with the current st­­re­­ss of limited water resources, it has adopted various techniques for improving irrigation. However, till now, most of the sector activities are dependent on rain. Of the total 140.13 million hectares of sown area, the net irrigated area is 68.38 million hectares while 71.74 million hectares is unirrigated.

Indian Infrastructure takes a look at some of the water irrigation techniques practised in India…

Well and tube well irrigation

A tube well can be installed in areas rich in groundwater. There are various types of tube we­lls such as shallow wells, deep wells and

ar­­te­sian wells. The advantages of tube wells are that they are cost-effective and can provide wa­ter throughout the year. A deep tube well, operated by electricity, can irrigate an area as large as about 400 hectares. Also, tube wells do not lead to water wastage in terms of evaporation as in the case of surface wells. How­ever, the drawback of this method is that it results in the depletion of groundwater.

Wells and tube wells account for about 48 per cent of irrigation in India. Tube wells are mo­stly used in Uttar Pradesh, Haryana, Punjab, Bihar and Gujarat. The Uttar Pradesh government is planning to install 50,358 shallow tube wells to support small and marginal farmers entailing an investment of Rs 465.8 million. In financial year 2020-21, a total of 11,866 shallow tube wells were installed under the HKKP and as many as 70,838 under the Mukhya­­ma­n­­triLaghuSinchayee Yojana.

Tank irrigation

Tank irrigation is a traditional method of irrigation in India, which irrigates about 3 million hec­tares of land even today. In this method, a tank is developed by constructing a small bund out of earth or stones, built across a stream. These tanks have a long lifespan and are used for irrigation and other purposes. This technique is cost-effective but is heavily dependent on rainwater. Tank irrigation is widely used in Karna­taka, Madhya Pradesh, Maharashtra, Odisha, Kerala, the Bundelkhand area of Uttar Pradesh, Rajasthan and Gujarat. However, the sector has seen a decline in the use of this me­thod in the past few years. This can be attributed to the development of newer techniques such as micro-irrigation and drawbacks of tank irrigation methods like water loss due to evaporation, dependence on rainfall, etc.

Canal irrigation

Canals can be an effective irrigation source in areas with low-level relief, deep fertile soils, perennial water sources, and a large command area. There are two types of canal irrigation techniques – inundation canals and pe­re­nnial canals. Inundation canals are carved out of the river without any regulating system like weirs, etc. at their head. These provide irrigation ma­in­ly in the rainy season when the river is in fl­o­od and there is excess water. Perennial ca­­­nals are those which are carved out from pe­re­nnial rivers by constructing a barrage across the river. Most of the canals in India are perennial. The majority of canal irrigation is in the ca­nal network of the Ganga-Yamuna basin main­ly in Punjab, Haryana and Uttar Pradesh and some parts of Rajasthan and Bihar, while small local canal networks exist in Tamil Nadu, Kar­nataka and Kerala.

Micro-irrigation techniques

Micro-irrigation techniques are the modern techniques of irrigation being adopted globally. The water-saving approach of this method has paved the way for increased water use effici­ency of 75 per cent to 95 per cent. Further­mo­re, micro-irrigation has enabled fertigation, re­sul­ting in a balanced nutrient application and thus reduced fertiliser requirements.

India initiated micro-irrigation in 1992 and recognised it as a thrust area in 2006. The In­­­dian government launched nationwide sche­mes such as  the National Mission on Micro Ir­ri­gation and National Mission for Sustainable Agriculture in 2006 to promote micro-irrigation in the country. In July 2015, the HKKP mission un­der the PMKSY scheme aimed at paying a 51 per cent subsidy to farmers for installing micro-irrigation facilities.

Currently, Sikkim, Andhra Pradesh, Karna­­ta­ka and Maharashtra have more than half of their net cultivable area under micro-irrigation. Some of the micro-irrigation techniques inclu­de drip-irrigation, sprinkler irrigation, sub-irrigation and seepage irrigation, and bubbler irrigation.

In June 2022, the Haryana government la­­un­ched a state-level flagship programme on drip irrigation for water needs in fields. Under this scheme, 1,445 villages have been identified with water tables below 100 feet depth for im­plementation of the scheme. A one-day seminar and demonstration were also organised for farmers to increase awareness regarding drip irrigation at 7,500 locations across the st­ate, where water depth is below 100 feet.

In drip irrigation, water is applied near the plant root via emitters or drippers on or below the soil surface at a low rate ranging from 2 li­tres to 20 litres per hour. In the sprinkler irrigation technique, water is sprayed into the air and allowed to fall on the ground in a manner similar to rainfall. Sprinkler irrigation systems are ideal for irrigation on uneven terrain and in sh­allow soils. Further, in sub-irrigation and seepage irrigation techniques, the water is delivered directly to the root of plants from below the soil surface and is absorbed upwards. This method reduces the cost of labour but the installation and maintenance costs are high. Bubbler irrigation is a combination of drip irrigation and a sprinkler system. It works best for raised plant beds, trees and shrubs. The biggest disadvantage of this system is that it requires high maintenance for proper operation without which it may result in water loss.

The way ahead

The irrigation sector has seen increasing use of micro-irrigation technologies in the past few years. Micro-irrigation helps in improving effici­ency and addresses water scarcity problems. With half the cultivable land still dependent on rain, there is huge scope for the development of proper micro-irrigation technologies in the country. Currently, piped irrigation is also being promoted by the Ministry of Jal Shakti for the conveyance of irrigation water to avoid land acquisition and related issues. A minimum of 10 per cent micro-irrigation is mandatorily req­uir­ed for command area development works being funded by the ministry. In this regard, liberal central assistance has been provisioned for projects adopting micro-irrigation, either through supervisory control and data acquisition or otherwise.

In September 2020, the Ministry of Ag­ri­culture and Farmers’ Welfare announced a target of covering 10 million hectares of land by 2025 under micro-irrigation. As of February 2022, 13.78 million hectares of land has been covered under micro-irrigation in India. The government needs to continue to support farmers both financially and technically in adopting micro-irrigation methods at state or regional levels and also educate them about water scarcity and efficient use of water to reduce wastage.

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